In many processes involving conveyed particulate material it is desirable to periodically sample the material carried on the conveyor belts for anaylsis and control of the process. Sampling at the junction points between a main conveyor belt and a feeder belt can be cumbersome and samples retrieved may be inaccurate due to difficulties of sampling a proper cross section of the flow. Samplers which take material from the main belt must be exactly positioned in order to deal with the problems of stratification in which fines of the material traveling on the belt filter to the bottom. A sampler which does not take account of the fines will produce an inaccurate sample. Hand sampling may obtain an accurate cross section, but because the sampling process is not repeatable numerous variations in the sample introduced by human error result in unreliable data. Furthermore, it is difficult to obtain a sample which is large enough to accurately reflect the flow contents and yet which is small enough to be conveniently analyzed and stored.
What is needed is an apparatus which can automatically and consistantly sample one or more transition points on a conveyor belt system and which can retrieve a large cross sectional sample across the full width of the belt and the entire depth of the flow material, and which can reliably reduce the size of the sample for sample classification purposes.